Phonon-tuned bright single-photon source

TL;DR

This paper demonstrates that phonon interactions enable efficient, bright single-photon emission from quantum dots in micropillar cavities even when the emitter is detuned from the cavity resonance, simplifying fabrication.

Contribution

It reveals that phonon coupling relaxes the spectral matching requirement, allowing high-brightness single-photon sources without precise resonance tuning.

Findings

Achieved over 40% brightness despite large detuning

Phonon coupling induces a significant Purcell effect

Single-photon emission remains efficient across 15 cavity linewidths

Abstract

Pure and bright single photon sources have recently been obtained by inserting solid-state emitters in photonic nanowires or microcavities. The cavity approach presents the attractive possibility to greatly increase the source operation frequency. However, it is perceived as technologically demanding because the emitter resonance must match the cavity resonance. Here we show that the spectral matching requirement is actually strongly lifted by the intrinsic coupling of the emitter to its environment. A single photon source consisting of a single InGaAs quantum dot inserted in a micropillar cavity is studied. Phonon coupling results in a large Purcell effect even when the quantum dot is detuned from the cavity resonance. The phonon-assisted cavity enhanced emission is shown to be a good single-photon source, with a brightness exceeding $40$ \% for a detuning range covering 15 cavity linewidths.